Method for bleaching nuts

Abstract

A method and apparatus for bleaching the shells of in-shell nuts and for bleaching the meats of shelled nuts involves wetting the nuts with an alkaline solution and then with a peroxygen solution. The two substances react to form a bleaching agent which whitens the shell or nut meat. Slight mechanical brushing may be used to dislodge debris loosened by the process. The apparatus includes means for recycling the reagents through the system without causing the desired temperature and concentration of the reagents to deviate significantly from predetermined values.

We claim: 
     
       1. A method of bleaching nuts, comprising the steps of: (a) providing a plurality of downwardly inclined baffles, and further providing an alkaline solution and a peroxide solution;   (b) spraying nuts with the alkaline solution;   (c) draining the alkaline solution from the nuts by tumbling the nuts back and forth between the downwardly inclined baffles and by flowing the alkaline solution away from the nuts by surface tension on the baffles;   (d) drying the nuts; and then   (e) spraying the nuts with the peroxide solution.   
     
     
       2. The method of claim 1 wherein step (a) further provides a heated conveyor and wherein step (d) is performed by tumbling the nuts over the heated conveyor. 
     
     
       3. The method of bleaching nuts comprising: spraying nuts with a alkaline solution of sodium bicarbonate at a concentration of about 1 to 10% and a temperature of about 100 to 180 degrees F. and a sufficient quantity to thoroughly wet the nuts,   providing downwardly inclined baffles and draining the nuts by tumbling them back and forth between said baffles and flowing the alkaline solution away from the nuts by surface tension on the baffles;   drying the nuts, and then   spraying the nuts with a peroxide solution at a concentration of about 4 to 20% by moving said peroxide from a peroxide source to the nuts while recycling excess quantities of the peroxide solution to the nuts without returning the peroxide solution to said peroxide source.   
     
     
       4. The method of removing aflotoxin from nuts, comprising the steps of: (a) providing a plurality of downwardly inclined baffles, and further providing an alkaline solution and a peroxygen solution;   (b) spraying nuts with the alkaline solution;   (c) draining the alkaline solution from the nuts by tumbling the nuts back and forth between the downwardly inclined baffles and by flowing the alkaline solution away from the nuts by surface tension on the baffles;   (d) drying the nuts; and then   (e) spraying the nuts with the peroxygen solution to cause the alkaline solution and the peroxygen solution to chemically react on the surface of the nuts.   
     
     
       5. The method of claim 3 in which the method further provides a heated surface and in which the step of drying the nuts is performed by tumbling the nuts over said heated surface. 
     
     
       6. The method of claim 4 wherein: the step of providing an alkaline solution includes the step of providing a sodium bicarbonate solution; and   the step of providing a peroxygen solution includes the step of providing a hydrogen peroxide solution.   
     
     
       7. The method of claim 4 in which the providing step further provides a heated surface and in which the step of drying the nuts is performed by tumbling the nuts over said heated surface. 
     
     
       8. The method of removing aflotoxin from nuts, comprising (a) providing downwardly inclined baffles;   (b) spraying nuts with a alkaline solution of sodium bicarbonate at a concentration of about 1 to 10% and a temperature of about 100 to 180 degrees F. and a sufficient quantity to thoroughly wet the nuts,   (c) draining the alkaline solution from the nuts by tumbling the nuts back and forth between said downwardly inclined baffles and flowing the alkaline solution away from the nuts by surface tension on the baffles;   (d) drying the nuts; and then   (e) spraying the nuts with a peroxide solution at a concentration of about 4 to 20% by moving said peroxide from a peroxide source to the nuts while recycling excess quantities of the peroxide solution to the nuts without returning the peroxide solution to said peroxide source.   
     
     
       9. The method of claim 8 in which the providing step further provides a heated surface and in which the step of drying the nuts is performed by tumbling the nuts over said heated surface.